The present invention is directed to a technique for monitoring corrosion in a fire protection sprinkler system and, in particular, to such a technique utilizing coupons positioned in the system during use and subsequently removed for inspection. The invention finds application in both a wet pipe fire protection sprinkler system and in a dry fire protection sprinkler system.
The presence of standing water in fire protection sprinkler systems typically leads to corrosion in the piping network, valves, and the like. If left undetected, such corrosion may eventually lead to pitting and pinholes in the piping network and even system failure.
There are two general types of fire protection sprinkler systems. In a wet pipe fire protection sprinkler system, water is present under pressure at all times throughout the system. Therefore, when the fuse of a sprinkler head is actuated by heat, or the like, water is immediately discharged from the sprinkler head to extinguish the fire. Wet pipe sprinkler systems are typically used in areas that are heated so that the temperature does not drop below freezing, which could damage the system. In a dry fire protection sprinkler system, an electrically actuated valve or a pressurized gas holds water back from the pipe network, which is maintained generally free of all but a residual amount of water.
Dry fire protection sprinkler systems come in two varieties—dry pre-action fire protection sprinkler systems and dry pipe fire protection sprinkler systems. In a dry pre-action fire protection sprinkler system, an electrically or pneumatically operated valve holds water back from the piping network. A smoke or heat detector operates the valve when a fire condition exists in order to flood the piping network with water. The water is discharged when a sprinkler head is actuated by heat. Maintenance air may optionally be supplied under pressure to the piping network in the dry pre-action fire protection sprinkler system to allow monitoring of air pressure to detect leaks in the piping network. In a dry pipe fire protection sprinkler system, a pressurized gas, such as air, in the sprinkler system piping network keeps a levered valve closed to hold water back from the piping network. If a sprinkler head in a dry pipe fire protection sprinkler system is actuated by heat, the pressurized gas is discharged from the piping network thereby reducing gas pressure in the piping network. This allows the levered valve to open and water to enter the piping network to be discharged through the open sprinkler head(s) to apply water to extinguish the fire. Dry fire protection sprinkler systems are typically used in areas subject to freezing temperatures as well, as areas where water is undesirable, such as data centers, museums, and the like.